modify-syntax-entry is not loaded in emacs init? - emacs

Since I don't want underline char _ to break a word, I put the script:
(modify-syntax-entry ?_ "w")
in the Emacs init file. The purpose is that for words like test_test, to double click the word will select the whole word before and after _.
But for some reason, the script is not working in initialization.
If I run
M-x eval-buffer
Then it will start to be effective. Why is that?
BTW, all other setups in init are working well, it is only the modify-syntax-entry that requires an additional evaluation after the initial launch.

See the Elisp manual, node Syntax Basics. There you will see this:
Typically, each major mode has its own syntax table, which
it installs in all buffers that use that mode. For example, the
variable emacs-lisp-mode-syntax-table holds the syntax table used by
Emacs Lisp mode, and c-mode-syntax-table holds the syntax table used
by C mode. Changing a major mode’s syntax table alters the syntax in
all of that mode’s buffers, as well as in any buffers subsequently put
in that mode.
You need to change the syntax table of the current buffer (which will
typically make the change for all buffers in the same mode).
The current syntax table, that is, the syntax table of the current buffer, is returned by function syntax-table. So that is what you pass to modify-syntax:
;; Modify the CURRENT syntax table (not `standard-syntax-table').
(modify-syntax-entry ?_ "w" (syntax-table))
Function syntax-table is described in the Elisp manual, node Syntax Table Functions.
However, you seem to want to make this change for all buffers, whatever the mode. Is that right? That's probably a mistake.
What you should probably do is this:
Decide which modes you want to modify this way.
For those modes, put the call to modify-syntax-entry in a function that you add to the mode hook of each of those modes (using add-hook).
For example, to modify the syntax of, say, foo-mode:
(defun my-syntax () (modify-syntax-entry ?_ "w" (syntax-table)))
(add-hook 'foo-mode-hook 'my-syntax)

A sideways solution: replace your problematic line of code with
(global-superword-mode 1)
This will tell Emacs that you like your "word movements" to actually operate on identifiers rather than what Emacs traditionally defines as words. The advantage is that it keeps the normal definition of words for internal use, so it should in theory break less code than your approach.

Every buffer has its own syntax table, which is usually dependent on the major mode of the buffer. When you run your code in the Emacs init file, it just modifies the syntax table of the temporary buffer that's used while loading the file, not your regular buffers.
Most syntax tables inherit from the standard syntax table, so you can make your change to that table by giving another argument to modify-syntax-entry:
(modify-syntax-entry ?_ "w" (standard-syntax-table))

Related

how to prevent helm-swoop from returning symbol at point?

I would like to invoke M-x helm-swoop such that it does NOT return the symbol at point. I find that it always picks up undesired symbols, e.g. when I invoke M-x helm-swoop in org-mode, I get Swoop: \*, and I then have to delete the \* before I can enter my desired search term. How can I do this?
This has been bugging me as well, for exactly the same reason (swoop in an Org-mode buffer picking up heading characters), so this question motivated me to go and look.
Looking at the source, Helm-swoop calls helm-swoop-pre-input-function to populate the prompt, and by default this is set to a function that returns (thing-at-point 'symbol), which is what causes the problem in headings.
A quick test with the following in my init file seems to work:
(setq helm-swoop-pre-input-function
(lambda () nil))
This could certainly be improved by, for example, keeping the default behaviour in non-Org buffers but as I'm only really using swoop in Org buffers this is good enough for me.

The major mode name of emacs-lisp

I want to load emacs init files faster, so I use the 'eval-after-load.
For example, when I load clojure file, I just put
(eval-after-load 'clojure-mode
'do-something)
It works.
But when I try
(eval-after-load 'emacs-lisp-mode
'do-something)
It doesn't work. I wonder to know the right major mode name of emacs-lisp.
Thanks.
Please read the documentation of eval-after-load:
eval-after-load LIBRARY FORM
This function arranges to evaluate form at the end of loading the file LIBRARY, each time LIBRARY is loaded. If LIBRARY is already loaded, it evaluates form right away. Don't forget to quote form!
[…] LIBRARY can also be a feature (i.e., a symbol), in which case form is evaluated at the end of any file where (provide LIBRARY) is called.
You have to pass the name of the file or library, which defines the major mode, as argument.
While some modes are defined in files of the same name (e.g. clojure-mode in clojure-mode.el), many files a different name, especially if the actually define multiple major modes.
emacs-lisp-mode is defined in lisp-mode.el, along with some other modes for Emacs Lisp editing (e.g. lisp-mode as a generic Lisp language mode, or lisp-interaction-mode for *scratch* buffers).
Hence, use (eval-after-load 'lisp-mode …)
Also, you have to give a single sexp as second argument, so you'll likely want to use (eval-after-load 'lisp-mode '(do-something)), to call the function do-something.
If you are using a snapshot build of Emacs, use with-eval-after-load, i.e. (with-eval-after-load 'lisp-mode (do-something)). It allows for more than a single form, and doesn't require quoting.
Just eval with M-: the variable major-mode. It actually is emacs-lisp-mode.
Note that *scratch* is actually in lisp-interaction-mode.
As to what you're trying to do, use (eval-after-load "lisp-mode").
As explained by #lunaryom, the arg passed to eval-after-load is not a function name but a feature name, which is basically a file name. So you need to find the name of the file from which the function is loaded.
We could provide a feature like eval-after-defun, and indeed it might be a good idea to do so. If you'd like such a thing, ask for it via M-x report-emacs-bug.

How to disable underscore (_) subscripting in Emacs, TeX input method

On Emacs, while editing a text document of notes for myself (a .txt document, not a .tex document), I am using M-x set-input-method Ret TeX, in order to get easy access to various Unicode characters. So for example, typing \tospace causes a "→" to be inserted into the text, and typing x^2 causes "x2" to be inserted, because the font I am using has support for Unicode codepoints 0x2192 and 0x00B2, respectively.
One of the specially handled characters in the method is for the underscore key, _. However, the font I am using for Emacs does not appear to have support for the codepoints for the various subscript characters, such as subscript zero (codepoint 0x2080), and so when I type _0, I get something rendered as a thin blank in my output. I would prefer to just have the two characters _0 in this case.
I can get _0 by the awkward keystroke sequence _spacedel0, since the space keystroke in the middle of the sequence causes Emacs to abort the TeX input method. But this is awkward.
So, my question: How can I locally customize my Emacs to not remap the _ key at all when I am in the TeX input method? Or how can I create a modified clone (or extension, etc) of the TeX input method that leaves out underscore from its magic?
Things I have tried so far:
I have already done M-xdescribe-key on _; but it is just bound to self-insert-command, like many other text characters. I did see a post-self-insert-hook there, but I have not explored trying to use that to subvert the TeX input method.
Things I have not tried so far:
I have not tried learning anything about the input method architecture or its source code. From my quick purview of the code and methods. it did not seem like something I could quickly jump into.
So here is the solution I just found: Make a personalized copy of the TeX input method, with all of the undesirable entries removed. Then when using M-x set-input-method, select the personalized version instead of TeX.
I would have tried this earlier, but the built-in documentation for set-input-mode and its ilk does not provide sufficient guidance to the actual source for the input-methods for me to find it. It was only after doing another search on SO and finding this: Emacs: Can't activate input method that I was able to get enough information to do this on my own.
Details:
In Emacs, open /usr/share/emacs/22.1/leim/leim-list.el and find the entry for the input method you want to customize. The entry will be something like the following form:
(register-input-method
"TeX" "UTF-8" 'quail-use-package
"\\" "LaTeX-like input method for many characters."
"quail/latin-ltx")
Note the file name prefix referenced in the last element in the form above. Find the corresponding Elisp source file; in this case, it is a relative path to the file quail/latin-ltx.el[.gz]. Open that file in Emacs, and check it out; it should have the entries for the method remappings, both desired and undesired.
Make a user-local copy of that Elisp source file amongst your other Emacs customizations. Open that local copy in Emacs.
In your local copy, find the (quail-define-package ...) form in the file, and change the name of the package; I used FSK-TeX as my new name, like so:
(quail-define-package
"FSK-TeX" "UTF-8" "\\" t ;; <-- The first argument here is the important bit to change.
"LaTeX-like input method for many characters but not as many as you might think.
...)
Go through your local copy, and delete all the S-expressions for mappings that you don't want.
In your .emacs configuration file, register your customized input method, using a form analogous to the one you saw when you looked at leim-list.el in step 1:
(register-input-method
"FSK-TeX" "UTF-8" 'quail-use-package
"\\" "FSK-customized LaTeX-like input method for many characters."
"~/ConfigFiles/Elisp/leim/latin-ltx")
Restart Emacs and test your new input-method; in my case, by doing M-x set-input-method FSK-TeX, typing a_0, and confirming that a_0 shows up in the buffer.
So, there's at least one answer that is less awkward once you have it installed than some of the workarounds listed in the question (and as it turns out, are also officially documented in the Emacs 22 manual as a way to cut off input method processing).
However, I am not really happy with this solution, since I would prefer to inherit future changes to TeX mode, and just have my .emacs remove the undesirable entries on startup.
So I will wait to see if anyone else comes up with a better answer than this.
I did not test this myself, but this seems to be the exact thing you are looking for:
"How to disable underscore subscript in TeX mode in emacs" - source
Two solutions are given in this blogpot:
By the author of the blogpost: (setq font-lock-maximum-decoration nil) (from maximum)
Mentioned as comment:
(eval-after-load "tex-mode" '(fset 'tex-font-lock-subscript 'ignore))
The evil plugin for vim-like modal keybinding allows to map two subsequent presses of the _ key to the insertion of a single _ character:
(set-input-method 'TeX)
(define-key evil-insert-state-local-map (kbd "_ _")
(lambda () (interactive) (insert "_")))
(define-key evil-insert-state-local-map (kbd "^ ^")
(lambda () (interactive) (insert "^")))
When _ and then 1 is pressed, we get ₁ as before, but
when _ and then _ is pressed, we get _.
Analogous for ^.
As already explained in pnkfelix answer, it seems we have to make a personalized copy of the TeX input method. But here comes a lighter way to do that, without any file tweaking. Simply put the following in your .emacs :
(eval-after-load "quail/latin-ltx"
'(let ((pkg (copy-tree (quail-package "TeX"))))
(setcar pkg "MyTeX")
(assq-delete-all ?_ (nth 2 pkg))
(quail-add-package pkg)))
(set-input-method 'TeX)
(register-input-method "MyTeX" "UTF-8" 'quail-use-package "\\")
(set-input-method 'MyTeX)
The important part is the assq-delete-all line in the middle that remove all shortcut entries starting with _. It's a bit of a lisp hack but it seems to work. Since I'm also annoyed by the shortcuts starting with - and ^, I also use the following two lines to disable them :
(assq-delete-all ?- (nth 2 pkg))
(assq-delete-all ?^ (nth 2 pkg))
Note that afterwards you can M-x set-input-method at any time and indicate TeX or MyTeX to switch between the pristine TeX input method or the customized one.

Font-locking for SQL-MODE inside of ORG-MODE not font-locking

Related to question: org-mode: fontify code blocks natively
I've got the latest org-mode and emacs versions as of November 1, 2012 (org stored in org-20121105).
I've also got the sql-mode that comes with emacs-24.
I've got fontification turned one:
;; fontify code in code blocks
(setq org-src-fontify-natively t)
Yet this does not fontify in my org documents. Java, bash, etc. all work.
#+BEGIN_SRC SQL
SELECT foo FROM bar
#+END_SRC
When I open a file foobar.sql, the mode indicator says SQL[ANSI] (which I also tried as the source type), and font-locking works.
Thanks in advance for any tips.
Firstly, the name of the SRC block mode is case-sensitive. It should be sql instead of SQL.
#+BEGIN_SRC sql
SELECT foo FROM bar
#+END_SRC
Secondly, the initial font-lock of sql-mode seams not to highlight SQL keywords, (at least to me, it looks no difference no matter you turn it on or off). Therefore, you need to specify which kind of SQL you want to highlight. If you are using MySQL for example:
(add-hook 'sql-mode-hook
(lambda ()
(sql-highlight-mysql-keywords)))
Then Restart Emacs. It should work now.
Oh, wait, try putting #+BEGIN_SRC sql in lower case. See here for identifiers.
Try refreshing the display, by making the block be reparsed (break the syntax and undo, or something). It often happens to me with python or bibtex blocks, but this fixes it.
I can't see why it wouldn't fontify inline if it finds the right mode when you C-c '.
Also, I'm afraid fontification, while being one of org-mode's nicer features, is not exactly perfectly handled. From the mailing list :
The fontification engine is not very powerful and get easily fooled.

How to make flyspell bypass some words by context?

I use Emacs for writing most of my writings. I write using reStructuredText, and then transform them to LaTeX after some preprocessing since I write my citations á-la LaTeX. This is an excerpt of one of my texts (in Spanish):
En \cite[pp.~XXVIII--XXIX]{Crnkovic2002} se brindan algunos riesgos
que se pueden asumir con el desarrollo basado en componentes, los
This text is processed by some custom scripts that deals with the \cite part so rst2latex can do its job.
When I activate flyspell-mode it signals most of the citation keys as spelling errors.
How can I tell flyspell not to spellcheck things within \cite commands.
Furthermore, how can I combine rst-mode and flyspell, so that rst-mode would keep flyspell from spellchecking the following?
reST comments
reST code literal
reST directive parameters and arguments
reST raw directive contents
Any ideas?
You can set the variable ispell-parser to the value 'tex so that flyspell will ignore (la)tex sequences. To do so, you can either set it manually in each buffer like so:
M-: (setq 'ispell-parser 'tex)
or you write a little function that will do that for you. Put the following in your .emacs file:
(defun flyspell-ignore-tex ()
(interactive)
(set (make-variable-buffer-local 'ispell-parser) 'tex))
Then you can still invoke it manually, using
M-x flyspell-ignore-tex
or you could add a hook that calls that function automatically whenever you edit a file of a certain type. You would do the latter by adding the newly defined function to your auto-mode-alist. Say your filenames typically end with ".rst", then add this line to your .emacs file:
(add-to-list 'auto-mode-alist '("\\.rst$" . flyspell-ignore-tex))
As for the second part of your question: making flyspell-mode ignore larger regions, such as, e.g., reST comments, is not easily achievable. It becomes clear when you think about the way flyspell works: it checks text on a word-by-word basis. For that, flyspell-word only looks at one word at a time which it sends to an ispell process running in the background. The ispell process does the dictionary lookup and returns whether or not the current word is correct. If flyspell-word had to check every single time whether or not the current word is part of a comment or other region that should not be checked, it would be rather slow, because that would include quite a bit of searching through the buffer.
Now of course, one could approach this a little bit smarter and first find the non-comment regions etc. and then do the word-by-word checking only in those parts that are outside of those regions - but unfortunately, that's not the way flyspell is implemented.
If you can do without the "fly" part, however, ispell-mode has a mechanism to customize which regions of a buffer can be skipped. This is done via the variable ispell-skip-region-alist. But although flyspell-mode works off ispell-mode, for the reasons outlined above that variable is not used by flyspell-mode.
You can also use flyspell-generic-check-word-predicate as I explained in this question at Super User.
(aspell's tex filter may do exactly what you want - but if you want a more general solution)
Although I am using the code below to persuade flyspell to not flag certain words with numbers in them,
you can use this sort of hook to match certain context.
looking-at starts at the position you want - so you may want to search backwards for start/end of whatever context you care about.
(when "another attempt to accept certain words flyspell/ispell/aspell flags as incorrect"
(defun flyspell-ignore-WordNumber99-stuff/ag (beg end info)
(save-excursion
(goto-char beg)
(cond
((or
(looking-at "\\bWord1\\b")
(looking-at "\\bWord99Foo\\b")
)
t)
(t nil)
)
)
)
)
(add-hook 'flyspell-incorrect-hook 'flyspell-ignore-WordNumber99-stuff/ag)